Field of the Invention
Exemplary embodiments of the present invention relate to a thin film transistor and a method of manufacturing the thin film transistor. More particularly, exemplary embodiments of the present invention relate to a thin film transistor having improved electrical stability and a method of manufacturing the thin film transistor.
Description of the Background
Generally, a display apparatus includes an array substrate including a switching element and an opposite substrate facing the array substrate. The switching element includes a gate electrode electrically connected to a gate line, a semiconductor layer insulated from the gate electrode, a source electrode electrically connected to a data line and the semiconductor layer, and a drain electrode spaced apart from the source electrode and electrically connected to the semiconductor layer.
For example, the types of switching elements for the display apparatus may be divided into an amorphous silicon thin film transistor (“TFT”), a poly silicon TFT, and an oxide semiconductor TFT.
The amorphous silicon TFT is uniformly formed on a large substrate in a low manufacturing cost. However, the amorphous silicon TFT has a relatively low charge carrier mobility. The poly silicon TFT has a charge carrier mobility higher than the amorphous silicon TFT, and a deterioration of a characteristic of the poly silicon TFT is less than the amorphous silicon TFT. However, a process of manufacturing the poly silicon TFT is complicated so that a manufacturing cost is high. The oxide semiconductor TFT may be manufactured in a low temperature process, may be formed in a large area, and may have a relatively high charge carrier mobility.
In a process of manufacturing the switching element, when the source electrode and the drain electrode react with the semiconductor layer, a conductive characteristic of the semiconductor layer may be changed. In addition, when the oxide semiconductor reacts with the source electrode and the drain electrode, a cation included in the oxide semiconductor may be deposited so that a wiring resistance may increase. Thus, the electrical stability and reliability of the switching element may decrease.
In addition, when the source electrode and the drain electrode react with an insulating layer or a passivation layer, the insulating layer or a passivation layer may be lifted off from the source electrode and the drain electrode. Particularly, when the insulating layer or the passivation layer of the oxide silicon TFT includes an oxide silicon, the insulating layer or the passivation layer may be lifted off more frequently and more seriously.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.